With the development of food processing techniques, various types of foods that may be kept for extended periods have been developed and sold on the market. These foods can be cooked by a simple means and within a short time, while providing the original taste. There have also been developments with respect to cooked rice, and various types of products and manufacturing methods are already known.
For instance, Japanese Patent Publication No. 34730/1971 discloses a method of manufacturing "instant rice", and Japanese Patent Publication No. 43222/1982 discloses a method of manufacturing rice for storage. However, these methods suffer from the following problems. Although the former method is capable of providing dried rice with a high content of pregelatinized starch, it necessitates steaming and boiling the rice over a long time period, and is thus disadvantageous with respect to the demand for reducing energy costs. The latter method necessitates steps which may lead to loss of the pregelatinized content typical of such steps being a boiling step, thus resulting in a reduction of the yield.